1. Field of the Invention
The present invention relates to an atomic beam source.
2. Description of the Related Art
As a type of atomic beam sources, one that controls the electron density in the discharge space by displacing an anode placed inside a tubular body serving as a cathode has been proposed in the related art (refer to PTL 1). It is described in PTL 1 that the atomic beam source can obtain a desired emitted atom density distribution per unit time at a low cost in a short time and, if used in a surface modifying apparatus, enables excellent surface treatment.
According to the atomic beam source of PTL 1, the cathode and the anode become sputtered by ions or the like generated in the discharge space and particles fallen therefrom are sometimes emitted from the atomic beam source. Thus, there has been proposed an atomic beam source that includes a casing that serves as a cathode and an electrode body that is disposed in the casing and serves as an anode that generates an electric field, in which at least part of the casing or the electrode body is formed of a material that can resist being sputtered by ions generated by the electric field (refer to PTL 2). It is described that the atomic beam source of PTL 2 can suppress emission of unnecessary particles.